Serogroup identification, phenotypic detection of hemolysis and extended spectrum beta-lactamases of Escherichia coli isolated from psittacine of illegal wildlife trade in Fortaleza, Brazil / Identificação de sorogrupo e detecção fenotípica de betalactamase de espectro estendido e produção de hemolisina em Escherichia coli isoladas de psitacídeos do tráfico de animais silvestres em Fortaleza-CE

This study aimed to identify serogroups of Escherichia coli important for human health in isolates from psittacine of illegal wildlife trade in Ceará State. In addition, hemolysis and production of Extended Spectrum Beta-Lactamases (ESBL) was assessed in the isolates. A total of 78 E. coli strains isolated from different Psittaciformes species from a wildlife rehabilitation center in Fortaleza, Brazil. The isolates used in this study were previously identified and stored. Serogroup identification was performed using polyvalent sera for EPEC (O55, O111, O119, O114, O125, O86, O126, O127, O128), EIEC (O136, O124) and EHEC (O157). ESBL detection was performed with double disk synergy method. For hemolysis detection, isolates were inoculated in blood agar base enriched with ovine blood. Only 31 (39.7%) isolates were seropositive and the most frequent were O127, O114, O128 and O111. There was no agglutination for serogroups O55, O124, O136 or O157. Considering both seropositive and seronegative isolates, 9 (11.5%) and 35 (44.9%) presented hemolysis and ESBL production, respectively. In conclusion, the investigated psittacine from illegal wildlife trade hosted ESBL-producing E. coli strains and some belong to important serogroups often linked to severe human infections.(AU)

Este trabalho teve como objetivo identificar sorogrupos de E. coli importantes para a saúde humana, oriundos de psitacídeos provenientes do tráfico no estado do Ceará, assim como detectar atividade hemolítica e produção de betalactamase de espectro estendido (ESBL). Foram testadas 78 cepas de Escherichia coli provenientes de psitaciformes do Centro de Triagem de Animais Silvestres, Fortaleza, CE. Para a identificação dos sorogrupos, utilizaram-se soros polivalentes EPEC (O55, O111, O119, O114, O125, O86, O126, O127, O128), EIEC (O136, O124) e EHEC (O157). Para detecção de ESBL, as cepas foram submetidas ao método de aproximação de disco e, para a detecção de hemolisina, foram plaqueadas em ágar sangue base enriquecido com sangue de carneiro. No geral, 31 (39,7%) das amostras foram soropositivas. Os sorogrupos mais frequentemente detectados foram O127, O114, O128 e O111. Não houve positividade para os sorogrupos O55, O124, O136 e O157. Considerando-se as amostras sororreagentes e não sororreagentes, observou-se que nove (11,5%) e 35 (44,9%) cepas de E. coli apresentaram produção de hemolisinas e de ESBL, respectivamente. Em conclusão, constatou-se que psitacídeos provenientes do tráfico de animais silvestres albergam cepas de E. coli produtoras de ESBL e providas de importantes sorogrupos implicados em graves infecções humanas.(AU)

Chloroplast localization of Cry1Ac and Cry2A protein- an alternative way of insect control in cotton

BACKGROUND: Insects have developed resistance against Bt-transgenic plants. A multi-barrier defense system to weaken their resistance development is now necessary. One such approach is to use fusion protein genes to increase resistance in plants by introducing more Bt genes in combination. The locating the target protein at the point of insect attack will be more effective. It will not mean that the non-green parts of the plants are free of toxic proteins, but it will inflict more damage on the insects because they are at maximum activity in the green parts of plants. RESULTS: Successful cloning was achieved by the amplification of Cry2A, Cry1Ac, and a transit peptide. The appropriate polymerase chain reaction amplification and digested products confirmed that Cry1Ac and Cry2A were successfully cloned in the correct orientation. The appearance of a blue color in sections of infiltrated leaves after 72 hours confirmed the successful expression of the construct in the plant expression system. The overall transformation efficiency was calculated to be 0.7%. The amplification of Cry1Ac-Cry2A and Tp2 showed the successful integration of target genes into the genome of cotton plants. A maximum of 0.673 µg/g tissue of Cry1Ac and 0.568 µg/g tissue of Cry2A was observed in transgenic plants. We obtained 100% mortality in the target insect after 72 hours of feeding the 2nd instar larvae with transgenic plants. The appearance of a yellow color in transgenic cross sections, while absent in the control, through phase contrast microscopy indicated chloroplast localization of the target protein. CONCLUSION: Locating the target protein at the point of insect attack increases insect mortality when compared with that of other transgenic plants. The results of this study will also be of great value from a biosafety point of view.

Gene detection and toxin production evaluation of hemolysin BL of Bacillus cereus isolated from milk and dairy products marketed in Brazil

Bacillus cereusis an ubiquitous, spore-forming bacteria that can survive pasteurization and the majority of the heating processes used in the dairy industry. Besides, it is a pathogen responsible for different types of food poisoning. One type of foodborne disease caused by B.cereusis the diarrheal syndrome, which is caused by the ingestion of vegetative cells producing toxins in the small intestine. One virulence factor for the diarrheal syndrome is the toxin hemolysin BL (HBL), a three-component protein formed by the L1, L2 and B components. In order to evaluate the presence of diarrheal strains isolated from milk and dairy products, 63 B. cereus isolates were obtained from 260 samples of UHT milk, pasteurized milk and powdered milk, sold in commercial establishments and from different brands. The isolates were subjected to the Polymerase Chain Reaction (PCR) for the detection of the encoding genes for the L1, L2 and B components and the toxin production capacity were evaluated with an immunoassay. A total of 23 [36.5%] isolates were identified carrying simultaneously the three tested genes, from which, 20 [86.9%] showed toxigenic capacity. 26 [41.3%] isolates did not carry any of genes tested and the other 14 [22.2%] were positive for one or two of them. The results showed a high toxigenic capacity among the B. cereus isolates able to produce the HBL, indicating a potential risk for consumers.

Antibiotic resistance of Vibrio parahaemolyticus isolated from pond-reared Litopenaeus vannamei marketed in Natal, Brazil

Ten out of fifty fresh and refrigerated samples of shrimp (Litopenaeus vannamei) collected from retailers in Natal (Rio Grande do Norte, Northeastern Brazil) tested positive for Vibrio parahaemolyticus. The Kanagawa test and multiplex PCR assays were used to detect TDH and TRH hemolysins and the tdh, trh and tlh genes, respectively. All strains were Kanagawa-negative and tlh-positive. Antibiotic susceptibility testing was done for seven antibiotics by the agar diffusion technique. Five strains (50 percent) presented multiple antibiotic resistance to ampicillin (90 percent) and amikacin (60 percent), while two strains (20 percent) displayed intermediate-level resistance to amikacin. All strains were sensitive to chloramphenicol. Intermediate-level susceptibility and/or resistance to other antibiotics ranged from 10 to 90 percent, with emphasis on the observed growing intermediate-level resistance to ciprofloxacin. Half our isolates yielded a multiple antibiotic resistance index above 0.2 (range: 0.14-0.29), indicating a considerable risk of propagation of antibiotic resistance throughout the food chain.

Phenotypic and genotypic characterization of Streptococcus uberis isolated from bovine subclinical mastitis in Argentinean dairy farms

The aim of this study was to investigate the phenotypic and genotypic characteristics of Streptococcus uberis isolated from subclinical mastitis (SCM) cases, and to examine the possible association between both characteristics. A total of 32 S. uberis were isolated from 772 quarter milk samples (SCM > 250,000 cells/ml) collected from 195 cows selected randomly from 18 dairy farms located in Argentina. The S. uberis strains were characterized phenotypically by the presence of virulence factors as plasminogen activator factor (PAF), hyaluronidase (HYA), capsule (CAP) and CAMP factor, and were further characterized genotypically by pulsed-field gel electrophoresis (PFGE). S. uberis strains expressed plasminogen activator factor, hyaluronidase or capsule (65.5 %, 56.3 %, 59.4 %, respectively), but only 25 % of isolates were CAMP factor positive. Thirteen different virulence profiles were identified on the basis of the combination of virulence factors. Eighteen PFGE patterns with 90% of similarity were identified among 32 S. uberis. A great diversity of virulence profiles and PFGE patterns were present among dairy farms. S. uberis strains with the same PFGE pattern showed different virulence profiles. Bovine S. uberis strains causing SCM included in the present study showed heterogeneity in regard to their phenotypic and genotypic characteristics, and the PFGE patterns are not associated with the virulence profiles.

Caracterización fenotípica y genotípica de Streptococcus uberis aislados de mastitis bovina subclínica en tambos de Argentina. El objetivo de este estudio fue investigar las características fenotípicas y genotípicas de Streptococcus uberis aislados de casos de mastitis subclínica (MSC) y examinar la posible asociación entre ambas características. Un total de 32 cepas de S. uberis fueron aisladas de 772 muestras de leche de cuartos mamarios (MSC > 25 0000 células/ml) colectadas de 195 vacas seleccionadas al azar pertenecientes a 18 tambos lecheros localizados en Argentina. Las cepas de S. uberis fueron caracterizadas fenotípicamente sobre la base de la presencia de factores de virulencia tales como el factor activador del plasminógeno (FAP), la hialuronidasa (HIA), la cápsula (CAP) y el factor CAMP. Además, fueron caracterizadas genotípicamente por electroforesis de campos pulsados (PFGE). Las cepas de S. uberis expresaron el factor activador del plasminógeno, la hialuronidasa o la cápsula (65,5 %, 56,3 % y 59,4 %, respectivamente), pero solo el 25 % fueron CAMP positivas. Sobre la base de la combinación de los factores de virulencia se identificaron 13 perfiles de virulencia diferentes. Asimismo, se identificaron 18 patrones de PFGE con un 90 % de similitud entre las 32 cepas de S. uberis. Se presentó una gran diversidad de perfiles de virulencia y patrones de PFGE entre los tambos. Cepas con el mismo patrón de PFGE presentaron perfiles de virulencia diferentes. Las cepas de S. uberis causantes de MSC en bovinos incluidas en el presente estudio mostraron heterogeneidad con respecto a sus características fenotípicas y genotípicas, y los patrones de PFGE no estuvieron asociados con los perfiles de virulencia.

Virulence factors and genetic variability of uropathogenic Escherichia coli isolated from dogs and cats in Italy

In this study, the association between virulence genotypes and phylogenetic groups among Escherichia (E.) coli isolates obtained from pet dogs and cats with cystitis was detected, and fingerprinting methods were used to explore the relationship among strains. Forty uropathogenic E. coli (UPEC) isolated from dogs (n = 30) and cats (n = 10) in Italy were analysed by polymerase chain reaction (PCR) for the presence of virulence factors and their classification into phylogenetic groups. The same strains were characterized by repetitive extragenic palindromic (REP)- and enterobacterial repetitive intergenic consensus (ERIC)-PCR techniques. We found a high number of virulence factors such as fimbriae A, S fimbriae (sfa) and cytotoxic necrotizing factor 1 (cnf1) significantly associated with phylogenetic group B2. We demonstrated a high correlation between alpha-hemolysin A and pyelonephritis C, sfa, and cnf1 operons, confirming the presence of pathogenicity islands in these strains. In addition, UPEC belonging to group B2 harboured a greater number of virulence factors than strains from phylogenetic groups A, B1, and D. REP- and ERIC-PCR grouped the UPEC isolates into two major clusters, the former grouping E. coli strains belonging to phylogenetic group B2 and D, the latter grouping those belonging to groups A and B1. Given the significant genetic variability among the UPEC strains found in our study, it can be hypothesized that no specific genotype is responsible for cystitis in cats or dogs.

Enhancement of protective immune responses by oral vaccination with Saccharomyces cerevisiae expressing recombinant Actinobacillus pleuropneumoniae ApxIA or ApxIIA in mice

We previously induced protective immune response by oral immunization with yeast expressing the ApxIIA antigen. The ApxI antigen is also an important factor in the protection against Actinobacillus pleuropneumoniae serotype 5 infection; therefore, the protective immunity in mice following oral immunization with Saccharomyces cerevisiae expressing either ApxIA (group C) or ApxIIA (group D) alone or both (group E) was compared with that in two control groups (group A and B). The immunogenicity of the rApxIA antigen derived from the yeast was confirmed by a high survival rate and an ApxIA-specific IgG antibody response (p < 0.01). The highest systemic (IgG) and local (IgA) humoral immune responses to ApxIA and ApxIIA were detected in group E after the third immunization (p < 0.05). The levels of IL-1beta and IL-6 after challenge with an A. pleuropneumoniae field isolate did not change significantly in the vaccinated groups. The level of TNF-alpha increased in a time-dependent manner in group E but was not significantly different after the challenge. After the challenge, the mice in group E had a significantly lower infectious burden and a higher level of protection than the mice in the other groups (p < 0.05). The survival rate in each group was closely correlated to the immune response and histopathological observations in the lung following the challenge. These results suggested that immunity to the ApxIA antigen is required for optimal protection.

Hemoglobinuria paroxística por frío en el lactante / Paroxysmal cold hemoglobinuria

Diez días después del comienzo de molestias sugerentes de infección respiratoria alta viral, un paciente de 11 meses tuvo síntomas, signos y evidencia de laboratorio, de anemia hemolítica y hemoglobinuria que pudieron relacionarse con la exposición al frío. El estudio inmunológico demostró que en su sangre había anticuerpos de Donath-Landsteiner con actividad contra antígeno P. La hemólisis pudo ser controlada manteniendo al paciente en un ambiente calefaccionado

Enterotoxinas y hemolisinas en Klebsiella pneumoniae / Enterotoxins and hemolysins in Klebsiella pneumoniae

Se estudió la capacidad de producir exterotoxinas en cepas de Klebsiellas pneumoniae aisladas de lactantes internados con septicemia y diarrea. La actividad enterotóxica se investigó mediante las pruebas del ratón lactante y del intestino ligado de conejo, determinando respectivamente el incremento del peso intestinal y la acumulación de fluido en los segmentos ligados. Los resultados indicaron que las bacterias provenientes de sangre, intestino y líquido cefalorraquídeo presentaron efecto semejante al observado con Escherichia coli enteropatógena, pero con mayor reacción inflamatoria. Las klebsiella se aislaron inicialmente de materia fecal y luego de sangre, originando finalmente meningitis, que resultó mortal en cuatro de los ocho casos estudiados. La entetoxina posee actividad hemolítica, pero difiere de la hemolisina activa en presencia de agentes reductores, porque tiene un rango de especies sensibles más amplio; no se inactiva por contacto con el oxígeno; no requiere de grupos sulfhidrilos libres para hemolizar eritrocitos; no pierde actividad a 60-C y sólo está presente en un número reducido de cepas con klebolisina, que es la hemolisina activada por agentes reductores como el 2 mercaptoetanol

Hemolisinas de Listeria monocytogenes demostrables por activación con 2- mercaptoctanol / Demonstrable Listeria monocytogenes hemolysins by 2- mercaptocthanol activation

Jones y Seeliger, con el apoyo del Comité Internacional sobre Bacteriología Sistemática, Subcomité sobre Taxonomía de Listeria, han propuesto la necesidad de reemplazar la cepa de L. monocytogenes ATCC 15313 como prototipo en virtud de su incapacida de inducir hemólisis en medios gelificados que contienen 5 o 10% de hematíes de origen ovino o equino (método clásico). En este trabajo se demuestra que, si bien, la cepa ATCC 15313 no induce hemólisis en las condiciones anteriores es capaz de hemolizar hematíes de carnero cuando los sobrenadantes de cultivos en infusión cerebro corazón adicionado de 0,5% de glucosa son previamente activados con 2-mercaptoetanol, condición que resulta general para todas las cepas de L. monocytogenes ensayadas. Igualmente la cepa ATCC 15313 induce lisis en medio gelificado de agar base sangre con hematíes de carnero cuando es cultivada en microaerofilia. Se estudiarion 13 cepas caracterizadas originalmente com L. monocytogenes. Se demuestra que la presencia de hemolisinas por el método directo y/o detección por activación con 2-mercaptoetanol es compatible con la identificación como L. monocytogenes, por lo cual se recomienda la inclusión de estaspruebas en todo estudio identificatorio. Además el estudio de capacidad hemolítica no puede obviar la prueba en microaerofilia. La ausencia de capacidad hemolítica en todas estas condiciones de ensayo es un factor de importancia para cuestionar la identificación de una cepa como L. monocytogenes

Improved method, using staphylococcal beta-hemolysin, for detection of hemolysin(s) produced by Vibrio cholerae biotype El Tor.

A tube test using brain heart infusion broth and staphylococcal B-lysin (HIBL) was devised to improve the detection of Vibrio cholerae El Tor hemolysin. Fifty six (100%) strains of V. cholerae serotypes Ogawa (28) and Inaba (28) were positive by the hemolysin test whereas 4 Inaba and 2 Ogawa were positive by a standard tube test using heart infusion broth (HIB) and 20 Ogawa and 18 Inaba were positive by another tube test using HIB containing glycerol (HIBG). Seven classical V. cholerae strains tested were negative by the 3 methods. The HIBL tube test was faster and more sensitive than the other 2 methods and showed that hemolysin was present that would otherwise have gone undetected by the other 2 methods using HIB or HIBG.